Is there an AND option on the rules condition in .gitlab-ci.yml?

I want to create some nested conditions: i need this pipeline to work when it is a merge or merge request and with certain name start "feature". So, is there an AND condition in the 'only' option for jobs?

No there is not. You must use rules.

test:
  stage: test
  script:
    - echo "test"
  rules:
    - if: '$CI_PIPELINE_SOURCE == "merge_request_event" && $CI_MERGE_REQUEST_TITLE =~ /^feature/'